Field of the Invention
The present invention relates to an electronic component, in particular an SAW component operating with surface acoustic waves with contacts suitable for SMD mounting. The component has electrically conductive structures on a piezoelectric substrate sealingly encapsulated against environmental influences by a cap cover. Through-plated holes are formed in the cover to connect the terminal pads of the electrically conductive structures to solderable metallized areas on the cover. The invention also pertains to a method of producing such an electronic component.
An earlier, commonly owned application No. 08/743,540 (see international published application WO 95/30276) describes an encapsulation for electronic components with a cap that seals component structures on a substrate. The cap is formed by a cover which is provided on the substrate and has cutouts accommodating the component structures in regions thereof. Such an encapsulation protects the component structures against environmental influences, with the result that electronic components encapsulated in such a way can be used directly in further applications, without the need for an additional housing.
U.S. Pat. No. 4,639,631 to Chason et al. describes am SMD type SAW component, in which the piezoelectric substrate is arranged by means of electrically conductive epoxy resin above a mounting plate. A cap is placed over the substrate and sealingly seated on the mounting plate. Electrical contact with the electrically active structures on the piezoelectric substrate is in this case made via the electrically conductive epoxy resin, a through-plated hole in the cap plate part and mounting plate part and metallized areas on the outside of the cap and mounting plate.
The three-piece configuration of the prior art component--mounting plate, piezoelectric substrate and cap--is quite complex. Furthermore, the component cannot be mass-produced at a reasonable cost.
With increasing miniaturization, there is an aim to produce components which occupy minimum casing volume and have a low physical height. Such requirements arise, for example, when electronic components are used in smartcards, such as telephone cards or credit cards. Components with encapsulation according to the above-noted commonly owned application No. 08/743,540 satisfy these requirements in an optimum manner.